27/12/2025
Iselin Disease vs Os Vesalianum
Lateral foot pain in adolescents — don’t mislabel it as a fracture
Site: Base of 5th metatarsal
Population: Children & adolescents, often athletes
🔹 Iselin Disease
• Traction apophysitis of the 5th metatarsal base
• Caused by repetitive pull of peroneus brevis
• Seen in skeletally immature patients
• X-ray: Fragmented, irregular apophysis parallel to metatarsal shaft
• MRI (if needed): Bone marrow edema at apophysis
Management:
✔ Activity modification
✔ NSAIDs / ice
✔ Short-term immobilization if symptomatic
❌ Surgery rarely indicated
🔹 Os Vesalianum
• Accessory ossicle at the base of 5th metatarsal
• Congenital, often bilateral
• Usually asymptomatic incidental finding
• X-ray: Smooth, corticated, well-defined ossicle with synchondrosis
Management:
✔ Reassurance
✔ Treat only if symptomatic
✔ Excision — extremely rare
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Key Clinical Pearl
❌ Misdiagnosed as avulsion or Jones fracture → overtreatment
✅ Correct radiologic interpretation prevents unnecessary casting or surgery
